Update: Mystery of the AZAZ909 Call Sign

I love a good military mystery, don't you? Well here is one that has stumped me for quite a while. As my old friend Jack NeSmith use to say, "guess your Google isn't so strong this morning Chief."

In the Mode-S call sign block of some US Army a/c I see the call AZAZ909. I have seen this call associated with Cessna UC-35 aircraft flown by the OSACOM PATD at Joint Base Andrews NAF, MD (KADW), specifically:

97-00104 AE012E
98-00008 AE036E
98-00009 AE036F
00-01053 AE093C
01-00301 AE093D

And in the recent past by the US State Department Air Wing Patrick AFB, FL (KCOF)

Alenia C-27A Spartan #N12310 A0616B
Alenia C-27A Spartan #N23743 A22581

And just now the mystery of the AZAZ909 c/s just deepened. Appears the Russians are using at also.

See the following:
https://thesaker.is/a-few-military-secrets-to-put-in-your-pipe-and-smoke-by-scott/

And there are now other links about the Russians using AZA909 as well.

So does anyone want to hazard a guess what this AZAZ909 Mode-S call sign is all about?